As the world inches forward towards a post-COVID era, people are becoming increasingly cognizant of their health. Though vaccines are available and progressive treatments are in hand, people are trying to find ways to prevent and combat both COVID-19 or whatever foreign pathogens come our way. Too many people have learned the hard way that a surprise attack on an unfortified fortress can have devastating consequences. Though a bolstered immune system may not be a panacea, it can definitely help put up a good and effective fight against the myriad pathogens out there, including COVID-19.
In a nutshell, the immune system has a three-pronged approach towards battle. It starts with a filtering system to help keep intruders out. This system includes the epithelial layers in the gastrointestinal and respiratory tract, antimicrobial molecules and a low pH in the stomach (which produces an acidic and inhospitable environment for pathogens to thrive in).
Next, the immune system identifies and eliminates pathogens. Macrophages and dendritic cells swallow and digest intruders. T lymphocytes stimulate B lymphocyte cells to produce antibodies that bind to bacteria and/or viruses. Natural killer cells and T lymphocytes produce interferons, which prevent viral replication.
Lastly, our immune system can produce and hold onto immunological memory of pathogens. This allows for a quick defense/slaying if a certain intruder dares to show its face again. Memory is produced by memory T and B lymphocytes and antibodies.
Vitamins and minerals (also known as micronutrients) are essential to the integrity and function of the immune system. They help maintain the epithelial layers, aid in the production of the antimicrobial molecules, regulate inflammatory cytokine proliferation, inhibit viral replication, promote the ingestion of pathogens (also known as phagocytosis) and stimulate antibody production.
Though there are many micronutrients that can be discussed, the one that’s hiding under the radar is vitamin D. Many are deficient and don’t realize how vital it is for the human body and its natural defense system.
Vitamin D is a shining star, waiting to beam its light on us and help us maintain our body systems. It helps maintain those epithelial barriers discussed earlier, produces antimicrobial molecules and macrophage immune cells and boosts phagocytosis. It also plays a role in regulating the immune system, preventing it from becoming a potential monster onto itself. Though boosting immune function is important, overstimulating the system is not only not helpful, but it’s actually harmful, causing chronic inflammation and stress on the body.
More and more research studies are burgeoning on the possible connection between vitamin D and immune health. Cross-sectional studies in both the United Kingdom and the United States have found an inverse linear relationship between vitamin D levels and respiratory infection. (The lower your vitamin D level is, the higher at risk you are for respiratory infections.) In another study led by Sabetta et al. (2010), sufficient vitamin D levels have been linked to lower risk of acute respiratory infections in both adults and children. Several meta-analyses have shown that vitamin D supplementation reduces risk of respiratory tract infection attainment.
In terms of vitamin D and COVID-19, a report published by the Coronavirus National Information and Knowledge Center showed a circumstantial relationship between one’s level of vitamin D and risk of COVID-19 infection. The Center recommended people spend at least 20 minutes per day outside in the sun between the hours of 11 a.m. and 4 a.m. and/or take a vitamin D supplement of 800-1,000 International Units (IU) per day in order to have vitamin D levels within normal range.
Another report published by Leumit Health Care Services and Bar Ilan University’s Azrieli’s Faculty of Medicine states that low plasma vitamin D levels appear to be an independent risk factor for COVID-19 infections and hospitalizations. Those who had developed severe COVID-19 infections and were hospitalized had significantly low vitamin D levels.
D’Avilo et al. (2020) had also found that patients who tested positive for COVID-19 had lower levels of vitamin D than those who tested negative, though the significance was only found in those over 70 years old. Grant et al. (2020) has recommended for those deficient or at high risk for contracting COVID-19 taking 10,000 IU per day for several weeks followed by 5,000 IU per day to raise vitamin D levels to 40-60 ng/mL. High-dose supplementation may be a useful intervention as well for patients already combating a COVID-19 infection.
For those who aren’t deficient, there is debate on whether supplementation would help or harm. It’s important to check your vitamin D levels through bloodwork to know whether you’re deficient or not.
Regardless, though, the best way to attain micronutrients is through diet. It’s a much safer and naturally more regulated way than potential megadosing through supplementation (though some may need supplementation due to malabsorption issues and/or decreased appetite/food intake due to other medical issues).
Eating a diet rich in a variety of vegetables, fruits, whole grains, lean proteins and dairy will not only provide the nutrients needed for a sound defense system, but will also provide other powerhouse nutrients, such as phytochemicals and fiber. Vitamin D can be found in food sources such as salmon, herring, sardines, canned tuna, cod liver oil, mushrooms, egg yolks and fortified cow’s milk, soy milk, orange juice and breakfast cereals. Be sure to speak with your doctor about your vitamin D levels and potential need for supplementation. It may just save your life.
By Melissa Papir Kolb,
MS, RD
